The invention relates to a apparatus for feeding print products in a conveyed flow to a processing device. Such an apparatus comprises an arrangement for supplying print products by a first conveyor and a following second conveyor. A guide arrangement provided with side-adjustable guide members forms a center axis in the longitudinal direction, relative to the flow of conveyed print products, wherein the print products are aligned along the guide arrangement.
Apparatuses of the aforementioned type are used to supply print products to feeder hoppers of systems used for the further processing of print products. As used herein print products are understood to include printed sheets, cards, CD/DVD-ROM, flat goods samples, and the like, which are supplied in the form of bundles and for which the dimensions can vary over a wide format range.
The overlapping function is based, for example, on the principle of frictional adherence. It is known that the frictional value between two surfaces depends on their surface condition and is subject to considerable scattering. Since the color distribution on an imprinted page is generally irregular, it can additionally be concluded that the frictional value within the surface of a print product cannot be regular. A high number of the print products is provided with a fold along at least one edge or, for other reasons, the print products do not have the same thickness across the complete surface. This results in an irregular force distribution which additionally leads to an irregular distribution of the frictional forces. To restrict the influence of the aforementioned irregularities to a degree necessary for an acceptable function, the printed sheets are aligned centrally with respect to the conveyors and the second conveyor operates only in a narrow, central section, meaning in the region where the overlapping flow is formed. The first conveyor consists of at least one driven, circulating conveying means, e.g. chains, belts, or toothed belts, wherein the conveying direction is approximately horizontal or is slightly inclined in the movement direction. The second conveyor also consists of at least one driven, circulating conveying means, for example chains, belts or toothed belts. Alternatively, the conveying means can also be embodied as a roller conveyor, comprising a plurality of driven rollers.
The first and second conveyors are drive-connected, which can be achieved either by installing a gear between the conveyors, or by using separate drives which are connected via a joint control unit.
The thickness of the conveyed flow on the second conveyor is of necessity predetermined by the speed ratio for the two conveyors relative to each other, wherein this ratio is preferably adjusted such that no gaps can develop between the print products, but that at least 2 print products will overlap and result in an overlapping flow that is as continuous as possible. Since the measurements for the print products to be processed can vary in all three dimensions, the hoppers for the further print processing machines as well as the feeding apparatuses are configured such that they can be adapted to the format.
The manner in which the format is adjusted transverse to the conveying direction for the feeding apparatus is determined by the mode of operation of the further print processing machine to be supplied, wherein three adjustment cases are known:    a) The adjustment is symmetrical (secured in the center);    b) The adjustment is exclusively on the left (secured on the right edge); or    c) The adjustment is exclusively on the right (secured on the left edge).
State of the art feeding apparatuses are configured symmetrical with respect to the format adjustment transverse to the conveying direction. The case a) is thus covered. For the cases b) and c), however, the complete conveying arrangement must be displaced to the side so that the longitudinal center axis of the conveyed flow coincides with the center axis of the products positioned inside the hopper for the further print processing machine. In principle this is possible, but it also involves an enormous expenditure in force and time since the feeding apparatus must be securely connected to the floor during the operation.
Furthermore conceivable is the installation of an alignment means between the feeding apparatus and the hopper for the further print processing machine, which alignment means pushes the print products into the correct position on the side. This solution, however, is technically very involved, is not secure with respect to process technology, and furthermore requires additional space in the conveying direction for meeting this function.
The feeding apparatus can also be divided into an immovable lower part and an upper part which can be displaced relative thereto. This solution, which is simple per se, has the serious disadvantage that the system would require more space in the transverse direction, thus occupying the empty space needed for operating the system between two adjacent feeding apparatuses.